In many mobile markets, large constituencies of mobile subscribers have insufficient economic capacity to operate a mobile phone on a credit account, commonly called a post-paid mobile account. Such users are referred to herein as post-paid subscribers. In such markets, the largest constituencies of users are pre-paid subscribers. Pre-paid subscribers, either periodically or randomly, purchase set amounts of network credits which are then used to make voice calls or send text messages. Once those credits are consumed, the pre-paid subscribers are unable to make voice calls or send text messages until such time as they purchase and pre-pay for further credits.
In most of these same markets, mobile services such as voice and text messaging are provided using a method called Calling Party Pays (CPP). This is contrary to the typical North American model where each party pays for a call or text message, regardless of whether it is initiating or receiving such calls or messages. The CPP method is the most prevalent method in use in mobile markets. In theory, every subscriber will pay for calls or messages they initiate, and the recipient party pays nothing. In practice, those with the greatest economic capacity freely make calls and send messages whenever they want, while the least economically capable portion of the constituency must carefully use and conserve their credits preserve their credits. Therefore the natural tendency of less economically capable subscribers in CPP markets, when faced with the dilemma of wanting or needing to communicate, has been to find ways to effect such communication in the most efficient manner possible, where the best possible efficiency is to be the recipient of such communication.
The most prevalent method used to become the recipient is what is commonly referred to as “beeping” or “slamming”, where one subscriber will call another, let the line ring two or more times, and then hang up before calling charges apply. In some cases, this is done to affect a return call, wherein the calling party would then become the call recipient. In many cases however, where both parties are familiar, these intentionally dropped calls (IDC) have evolved into a primitive, but socially acceptable and cost effective methods for them to enjoy economically sustainable communication between such familiar parties or what could also be described as a form of “signaling”. This ability to signal can represent a significant portion of the value such subscribers' feel they should get from a mobile network subscription. These signaling methods consume considerable network resources and some percentage of available frequency spectrums deployed to deliver mobile services, such as control and voice channels allocated during such attempts, as well as utilizing capacity on other network infrastructure elements. In densely populated urban and suburban environments, this can lead to increased network congestion, lower quality of service and dropped calls and a myriad of other problems.
However, as mobile penetration rates grow, the average capacity of new subscribers to pay decreases, inexorably increasing the percentage of mobile network capacity consumed by subscribers communicating in such a manner.
Callers with limited financial capacity, that run out of credit, are termed Zero Credit callers, and as such any efforts they make to communicate or attempt to signal would be uneconomic, consuming resources with no revenue for the network. As long as a Zero Credit mobile device is registered however that device can continue to receive calls. As such, there are networks that use network based services strategies to provide some ability for such Zero Credit customers to indicate their desire to communicate with parties that are willing to place a return call. These methods typically require a Zero Credit caller to use inconvenient methods such as USSD based services which require a subscriber to input a series of characters beyond those numbers required to place the call. Other services look at network server based methods that flag call requests that are rejected by a prepaid service or other network services that reject call requests for a lack of credit or funds.